JPH08203652A - High temperature superconducting junction manufacturing method - Google Patents

Abstract

(57) [Abstract] [Purpose] A method for producing a high-temperature superconducting junction, which does not deteriorate the superconducting properties of the high-temperature superconductor to be joined and also orients the superconducting crystal in the joining portion to a high orientation, to obtain a good superconducting junction provide. In a method of joining high temperature superconductors 2 and 2'formed on a base material (silver plate) 1, a high temperature superconductor precursor 3 is interposed between the high temperature superconductors 2 and 2'to be joined,
Heating at a temperature at which the high-temperature superconductor crystal formed on the base material 1 does not decompose and / or melt, and a part of the high-temperature superconductor precursor 3 melts, and then the entire high-temperature superconductor precursor 3 crystallizes Then, a method of manufacturing a high temperature superconducting joined body for joining the high temperature superconductors 2, 2'to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high temperature superconducting assembly which is effective for producing a large high temperature superconductor from a small high temperature superconductor which is relatively easy to produce.

[0002]

2. Description of the Related Art A high temperature superconductor has a problem that it cannot be integrally manufactured in a large size or in a complicated shape because it is difficult to machine because it has a narrow temperature range in which it can be fired and has low mechanical strength. There is a point. In order to solve this problem, a base material such as metal or ceramics having an appropriate size or shape is prepared in advance, a high-temperature superconductor is baked on the surface of this base material, and the base material and the high-temperature superconductor are joined together to form an integrated body. The method to make it is considered. As a method of joining the base material and the high-temperature superconductor to each other, for example, as shown in JP-A-5-145267, the high-temperature superconductors formed on the base material are brought into contact with each other to locally heat the joined portion. Then, a method of joining each layer of the composite base material of the base material and the high temperature superconductor has been proposed.

[0003]

However, since the high-temperature superconductor crystal is difficult to be densely sintered, the high-temperature superconductor is simply porous by heating and remains porous.
Good superconducting joining (joining in which the superconducting characteristics are connected without being interrupted in the middle) is difficult due to the gaps remaining between the high-temperature superconducting crystals, and the heating temperature is raised in order to obtain good superconducting joining. Therefore, problems such as decomposition or melting of the high-temperature superconductor crystal and reaction with the base material occur.

That is, a high-temperature superconductor is hard to sinter, and crystals are formed and grow under extremely narrow temperature conditions. Superconductor crystal powder is applied to the joint portion and heated to densify the joint portion. If you try to make superconducting joints by doing so, a high processing temperature is required, so the surrounding high-temperature superconductor changes its phase and disappears as a superconductor, or crystals other than high-temperature superconductor are generated. However, there is a problem in that

For example, the partial melting method, which is known as a method for obtaining good superconducting characteristics, is decomposed into a crystal having a high-temperature superconductor crystal and a melt to densify it, and then cooled to re-produce the high-temperature superconductor. This is a method of crystallizing into crystals, but if this is applied to the conditions of heat bonding, the surrounding high temperature superconductor will also be decomposed by the melt generated by the partial melting.
Therefore, even if only the joint portion is made into a superconductor by a partial heating and firing and a good joint is obtained, the surrounding high temperature superconductor is deteriorated in characteristics or becomes non-superconducting, so that a good superconducting joint is not eventually obtained. In order to avoid the deterioration of the characteristics, it is necessary to use a precise firing technique similar to that for firing the whole, but if the whole is fired, the meaning of joining is lost.

In order to avoid the above problems, the present invention does not heat the high temperature superconductor to be joined to a temperature at which it decomposes and / or melts, and a desirable plate-shaped high temperature superconductor crystal is formed on the substrate surface. It is intended to provide a method for producing a high-temperature superconducting joint, which can obtain a good superconducting joint that is oriented in parallel.

[0007]

Means for Solving the Problems In order to bond the high temperature superconductors formed on the substrate, the present inventors have made various high temperature superconductor precursors at a temperature lower than the temperature at which the high temperature superconductor crystals decompose. As a result of detailed investigation of the behavior of the body, it was found that the high-temperature superconductor precursor precipitates high-temperature superconductor crystals when heated, but depending on the method of preparation, it melts before crystallization to obtain a dense structure. It was As a result of further studying the example of melting, it is the composition that deviates from the composition of the high-temperature superconductor.By gradually melting the nearby structure while melting, it becomes the composition of the high-temperature superconductor. Precipitate crystals. That is, when a uniform composition is obtained for each particle of the powder by a method such as melting, it becomes difficult to melt in the heating step, the composition becomes a high-temperature superconductor, and high-temperature superconductor crystals are found to be deposited, and the present invention is completed. It was

The present invention relates to a method for joining high-temperature superconductors formed on a base material, wherein a high-temperature superconductor precursor is interposed between the high-temperature superconductors to be joined, and a high-temperature superconductor crystal formed on the base material. Of a high-temperature superconducting joint in which the high-temperature superconductor precursor is not melted and / or melted, and a part of the high-temperature superconductor precursor is melted Manufacturing method and high temperature superconductor precursor film is formed on a noble metal plate to obtain a composite material, and then the upper part between the high temperature superconductors to be joined with the high temperature superconductor precursor film part of the composite material facing downward The high temperature superconductor crystal formed on the base material does not decompose and / or melt after being placed on the substrate, and a part of the placed high temperature superconductor precursor is melted, and then the whole high temperature superconductor precursor is High temperature superheated by heating at the crystallization temperature HTS assembly for joining the body to each other about the preparation of.

In the present invention, the kind and composition of the base material is not particularly limited, but a material that can withstand the heating temperature of the high temperature superconductor and has mechanical strength, for example, a metal base material such as Inconel, stainless steel or Hastelloy. , Ceramics and the like are preferably used, and of these, Inconel is preferably used in terms of easiness of processing, thermal expansion coefficient and the like. If the high-temperature superconductor may cause an undesirable reaction with the base material in the heating step, silver on the surface of the base material,
It is used by forming a film of noble metal such as gold or a film of magnesium oxide. When forming a film of a noble metal, it is preferable to form a film of copper or a copper alloy as a base metal because the film of the noble metal can be prevented from peeling off.

The high temperature superconductor precursor is a material obtained by weighing, mixing, and calcining raw materials such as oxides and carbonates so as to have the composition of the high temperature superconductor, or weighing, mixing, calcining and / or melting the raw materials. It is preferable to use a mixture of two or more kinds of powders that have been post-pulverized. The high-temperature superconductor precursor is preferably melted at a temperature below the decomposition temperature of the high-temperature superconductor, and in order to generate high-temperature superconductor crystals, it is preferable to use fine powder in which particles of each composition are uniformly dispersed,
Its average particle size is easy to melt, and it is easy to handle.
It is preferably 15 μm, and more preferably 3 to 10 μm.

The high-temperature superconductor to be joined is different from the high-temperature superconductor precursor to be interposed, and when the raw materials are mixed and then made into a uniform composition up to the particle unit of the powder by a method such as melting, the crystal of the high-temperature superconductor is formed. It is preferable because the content is high and abnormal behavior such as generation of a different phase can be reduced in the heating step. Further, addition of silver is preferable because it has an effect of promoting the generation of crystals.

To the high temperature superconductor precursor, 50 high temperature superconductor crystal powder having the same crystal structure as the high temperature superconductor to be joined is added.
If the content is wt%, the crystal is easy to grow, the growth direction can be controlled, and the production can be performed at low cost, which is preferable.

There is no particular limitation on the method for interposing the high temperature superconductor precursor between the high temperature superconductors. For example, powder of the high temperature superconductor precursor is sprayed, or a liquid high temperature superconductor precursor in the form of a slurry or a paste. It can be intervened by a method of applying a body or laminating a sheet-shaped high temperature superconductor precursor.
The high temperature superconductors may be overlapped with each other, or the high temperature superconductor precursors may be arranged side by side and interposed between the high temperature superconductors.

As the noble metal plate forming the film of the high temperature superconductor precursor, silver or an alloy plate containing silver as a main component is preferably used. There is no particular limitation on the method of forming the film of the high temperature superconductor precursor, but if the high temperature superconductor precursor formed into a sheet is pressed onto a noble metal plate and the formed product is bonded to the joint, the high temperature superconductor crystal is formed. Are preferred, and the growth direction of the high-temperature superconductor crystal can be controlled, which is preferable.

There is no particular limitation on the kind of the superconductor used for the high temperature superconductor precursor and the high temperature superconductor to be joined. For example, a Bi type high temperature superconductor, a Y type high temperature superconductor,
Although a Tl-based high temperature superconductor or the like can be applied, it is preferable to use a Bi-based high temperature superconductor in the present invention because a good superconducting junction can be easily obtained. 22 for Bi-based high-temperature superconductors
There are 12 phases, 2223 phases, etc. Of these, Bi system 221
The two phases are preferable because they are easy to operate and the crystal growth rate is relatively high.

The heating conditions for joining the high-temperature superconductors to each other are that the superconductor crystals formed on the substrate are not decomposed and / or melted, and a part of the interposing high-temperature superconductor precursor is melted, After that, it is necessary to heat at a temperature at which the entire high temperature superconductor precursor is crystallized, and under other conditions, problems such as difficulty in superconducting bonding and deterioration of superconducting properties occur. The optimum temperature for heating varies depending on the firing conditions such as the crystal grain size of the high-temperature superconductor precursor, the oxygen partial pressure of the surroundings, and the heating rate, and is appropriately selected. The firing atmosphere is preferably atmospheric air or an atmosphere in which the oxygen partial pressure is controlled.

[0017]

EXAMPLES Examples of the present invention will be described below. The present invention is not limited to these. Example 1 Bismuth oxide having a purity of 99.9% by weight or more (manufactured by Kojundo Chemical Laboratory, 3N) 466 g, strontium carbonate (manufactured by Kojundo Chemical Laboratory, 3N) 295.2 g, calcium carbonate (manufactured by Kojundo Chemical Laboratory) 3N) 100.1 g and cupric oxide (manufactured by Kojundo Chemical Laboratory, 3N) 159.1 g are weighed and put in a synthetic resin ball mill together with 2 kg of synthetic resin balls having a diameter of 10 mm and 1 kg of distilled water for 72 hours. Mixed. The mixed solution was dried at 100 ° C for 24 hours, the dried powder was transferred to a silver container and calcined at 820 ° C for 5 hours. After calcination, a high temperature superconductor precursor was obtained by dry grinding to an average particle size of 7 μm. The body (A) was obtained. This high temperature superconductor precursor (A)
Was an amorphous body with 2212 phase containing about 6% by weight and a small amount of unidentifiable crystals.

Next, the high temperature superconductor precursor (A) obtained above was placed in a zirconia container and heated at 1050 ° C. for 2 hours, and then the contents were poured onto a silver plate and rapidly cooled. Melt powder (A) by dry pulverization to an average particle size of 8 μm
I got

Next, 100 parts by weight of the molten powder (A) was mixed with polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd., trade name BL-2).
5 parts by weight, 2 parts by weight of dibutyl phthalate (manufactured by Wako Pure Chemical Industries, reagent first grade) and 15 parts by weight of ethyl alcohol (manufactured by Wako Pure Chemical Industries, reagent first class) were added and mixed, and then vacuum degassing was performed to obtain a slurry. Is supplied onto a polyester film (made by Toray) having a thickness of 100 μm, and the green sheet (A) having a thickness of 150 μm is formed by the doctor blade method.
I got

Thereafter, the green sheet (A) obtained above was thermocompression-bonded on a silver plate having a thickness of 0.1 mm at 60 ° C. under the condition of 10 MPa, and baked at a cross-sectional flow rate of 5 cm / min while flowing air to crystallize. Were sufficiently grown to be oriented and have a smooth surface, and the temperature conditions under which a high-temperature superconductor crystal was obtained were investigated. As a result, it was confirmed that the maximum temperature was in the range of 872 to 886 ° C, the holding time was within 2 hours, and the cooling rate was 5 ° C / hour or less at 850 ° C or higher. Therefore cross-sectional flow velocity 5
While flowing air at cm / min, heat to 883 ° C, hold for 30 minutes, and then cool to 850 ° C at a rate of 2 ° C / hour,
Then, it was cooled to room temperature at a rate of 100 ° C./hour to obtain a superconducting composite in which a high temperature superconductor was formed on a silver plate. Then, in order to investigate the temperature at which the superconductor crystal of the obtained superconducting composite melts, the superconducting composite was taken out of the furnace after changing the temperature by 1 ° C for 1 minute from 860 to 890 ° C for 20 minutes.
The crystal state was examined by the X-ray diffraction method. As a result, when the temperature exceeds 873 ° C., the contained Bi-based 2212 phase crystal disappears,
Since a large amount of 2201 crystals were detected, the heating temperature limit was set to 873 ° C.

On the other hand, a green sheet (B) (high temperature superconductor precursor (B)) having a thickness of 170 μm is obtained through the same steps as the step of obtaining the green sheet (A) in 100 parts by weight of the high temperature superconductor precursor (A). Obtained. After this, the thickness of 0.
The high-temperature superconductor precursor (B) obtained above was thermocompression-bonded on a 1 mm silver plate under the conditions of 60 MPa and 10 MPa, and baked at a cross-sectional flow rate of 5 cm / min while flowing air to obtain a high-temperature superconductor precursor (B). ) Was partially melted and the temperature conditions under which a high-temperature superconductor crystal was obtained were investigated. As a result, it was confirmed that the maximum temperature was in the range of 865 to 875 ° C, the holding time was within 2 hours, and the temperature decreasing rate was 5 ° C / hour or less at 850 ° C or higher.

Next, in order to investigate the temperature at which the superconductor crystal of the high temperature superconductor precursor (B) melts, the temperature of the high temperature superconductor precursor (B) placed on a silver plate is increased by 1 ° C. from 860 to 890 ° C. Change and hold for 20 minutes, then take it out of the furnace,
The crystal state was examined by the X-ray diffraction method. As a result, at 871 ° C. or higher, the contained Bi-based 2212 phase crystals disappeared and 2201 crystals were detected in large amounts. The high temperature superconductor precursor (B) is 221 even if it is rapidly cooled from a temperature of 870 or lower.
A large amount of 2201 phase was detected together with 2 phases, and 868 ° C.
When reheated at the above temperature and then cooled, a large amount of columnar crystals that were not superconductors were generated.

The superconducting composite obtained above is abutted as shown in FIGS. 1 (a) and 1 (b), and the tips of the abutted silver plates 1, 1'are fixed by caulking. High temperature superconductor 2 formed on the silver plates 1, 1 ',
The high-temperature superconductor precursor (B) 3 obtained above was coated with butyl alcohol (a reagent manufactured by Wako Pure Chemical Industries, Ltd.) between the 2'and adhered, and the maximum temperature was kept at 868 ° C for 30 minutes in the atmosphere (heating Treatment) and then lowering the temperature to 850 ° C. over 15 hours,
Furthermore, it cooled to 20 degreeC over 5 hours, and obtained the high temperature superconducting joined body. In the cooling step, the atmosphere was changed to a nitrogen atmosphere from 680 ° C. In FIG. 1B, 4 is a silver plate 1,
It is a crimping portion 1 '.

The joint part and its periphery of the high temperature superconducting joint body obtained above were observed by a microscope and an X-ray diffraction method, and the critical current density (hereinafter referred to as Jc) was measured by a four-terminal method. As a result, Jc at a liquid nitrogen temperature of 77.3K of the high temperature superconductor
It is joined before the 8600A / mm ² and after the bonding 7400A / mm ²
Further, Jc of the joint portion was 6200 A / mm ² as a value calculated by the film thickness of the superconductor at the joint portion. In addition, the joining state of the joining portion was free from abnormal irregularities, foaming, different phases, etc. due to the flow of the high-temperature superconductor, and was well oriented parallel to the joining surface, and good joining was obtained.

Comparative Example 1 The same as Example 1 except that the heating temperature after the superconducting composites were butted and the high temperature superconductor precursor (B) was bonded between the high temperature superconductors formed on the silver plate was 864 ° C. A high temperature superconducting joint was obtained through the same steps. The joint portion of the obtained high temperature superconducting joint and its periphery were observed by a microscope and an X-ray diffraction method, and Jc was measured by a four-terminal method. As a result, the Jc at the liquid nitrogen temperature 77.3K of high temperature superconductors, before joining the 8600A / mm ² and after bonding are 8400A / mm ^2, also Jc of the joint portion is, superconductor film thickness of the joint portion The calculated value was 800 A / mm ² . Further, the joint portion was not glossy and showed small irregularities, and although the superconductor 2212 phase crystal was formed, it was very fine.

Comparative Example 2 The same as Example 1 except that the superconducting composites were butted and the heating temperature after the high temperature superconductor precursor (B) was adhered between the high temperature superconductors formed on the silver plate was 875 ° C. A high temperature superconducting joint was obtained through the same steps. The joint portion of the obtained high temperature superconducting joint and its periphery were observed by a microscope and an X-ray diffraction method, and Jc was measured by a four-terminal method. As a result, the Jc at the liquid nitrogen temperature 77.3K of high temperature superconductors, before joining the 8600A / mm ² and after bonding are 4300A / mm ^2, also Jc of the joint portion is, superconductor film thickness of the joint portion The calculated value was as low as 1200 A / mm ^2, and the high temperature superconductor melted and flowed out at the joint portion, and the total thickness of the high temperature superconductor was reduced to about 20 μm with respect to the set value of 100 μm. In addition, an abnormal phase (columnar crystal) was abnormally generated at the boundary of the joint.

Example 2 Only the high temperature superconductor portion was peeled off from the superconducting composite body obtained in Example 1 and lightly crushed in a mortar to obtain a 40 μm plate crystal. Then, in the same manner as in the step of obtaining the green sheet (A) of Example 1, 100 parts by weight of 70% by weight of the high temperature superconductor precursor (A) obtained in Example 1 and 30% by weight of the plate-like crystal were added. Through the above process, a 170 μm thick green sheet (C) (high temperature superconductor precursor (C)) was obtained.

Next, the superconducting composite obtained in Example 1 is abutted as shown in FIGS. 2 (a) and 2 (b), and both ends of the abutted silver plates 1 and 1'are swaged and fixed. After that, the green sheet (C) obtained above, that is, the high temperature superconductor precursor (C), is placed on a silver plate 6 having a thickness of 0.1 mm, which is different from the above.
7 was thermocompression bonded at 60 ° C. under the condition of 10 MPa to obtain a composite material 5. Next, the high temperature superconductor precursor (C) of the composite material 5
With the part of the lower side facing down, the high-temperature superconductor 2 of the superconducting composite,
Place it on the upper part between 2'and then 3 at 870 ° C in the atmosphere.
After holding for 0 minutes (heat treatment), the temperature was lowered to 850 ° C. over 15 hours and further cooled to 20 ° C. over 5 hours to obtain a high temperature superconducting joint. In the cooling step, the atmosphere was changed to a nitrogen atmosphere from 680 ° C.

The joint portion of the high-temperature superconducting joint body obtained above and its periphery were observed by a microscope and an X-ray diffraction method, and Jc was measured by a four-terminal method. As a result, the Jc of the high temperature superconductor at a liquid nitrogen temperature of 77.3K was 8600 A / mm ² before joining.
And 7900 A / mm ² after joining, and J
c is a value calculated from the thickness of the superconductor film at the joint portion, which is 980.
It was 0 A / mm ² . In addition, the joining state of the joining portion was free from abnormal irregularities, foaming, different phases, etc. due to the flow of the high-temperature superconductor, and was well oriented parallel to the joining surface, and good joining was obtained.

Example 3 300 g of bismuth oxide (manufactured by Kojundo Chemical Laboratory, 3N) having a purity of 99.9% by weight or more, strontium carbonate (manufactured by Kojundo Chemical Laboratory, 3N) 147.6 g, calcium carbonate (manufactured by Kojundo Chemical) Weigh 50.1 g of 3N) made by R & D and 79.5 g of cupric oxide (3N made by Kojundo Chemical Laboratory),
1 kg of synthetic resin balls having a diameter of 10 mm and 500 g of distilled water were put into a synthetic resin ball mill and wet mixed for 72 hours. The mixture is dried at 100 ° C. for 24 hours, the dried powder is transferred to a zirconia container and heated at 1050 ° C. for 2 hours,
The contents were poured onto a silver plate, rapidly cooled, and further dry pulverized to an average particle size of 8 μm by a ladle machine to obtain a molten powder (B).

On the other hand, separately from the above, bismuth oxide having a purity of 99.9% by weight or more (manufactured by Kojundo Chemical Laboratory, 3N) 166
g, strontium carbonate (manufactured by Kojundo Chemical Laboratory, 3N)
147.6 g, calcium carbonate (manufactured by Kojundo Chemical Laboratory,
3N) 50.0 g and cupric oxide (manufactured by Kojundo Chemical Laboratory Co., Ltd., 3N) 79.6 g are weighed, and 1 kg of synthetic resin balls having a diameter of 10 mm and distilled water 500 in a synthetic resin ball mill.
and wet mixed for 72 hours. The mixture is 100 ℃
For 24 hours, transfer the dried powder to a zirconia container, heat at 1050 ° C for 2 hours, then pour the contents onto a silver plate and quench, and further dry-mill to an average particle size of 8 μm with a raider machine. To obtain a molten powder (C).

Further, 102.2 g of the melted powder (B) and 65.4 g of the melted powder (C) obtained above were weighed so that the theoretical composition of the Bi type 2212 phase was obtained, and the melted powders (B) and ( C) 5 parts by weight of polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd., trade name BL-2), 2 parts by weight of dibutyl phthalate (manufactured by Wako Pure Chemical Industries, reagent first grade) and 100 parts by weight of ethyl alcohol (made by Wako Pure Chemical Industries, reagent first grade) ) 15 parts by weight were added and mixed, and then vacuum degassing was performed to obtain a slurry having a thickness of 1
It is supplied on a polyester film (made by Toray) of 00 μm and formed into a sheet by the doctor blade method to a thickness of 170 μm.
m green sheet (D) (high temperature superconductor precursor (D))
I got

Thereafter, the high-temperature superconductor precursor (D) obtained above was thermocompression-bonded on a silver plate having a thickness of 0.1 mm at 60 ° C. under the condition of 10 MPa, and fired while flowing air at a sectional flow rate of 5 cm / min. Then, a temperature condition under which a part of the high temperature superconductor precursor (D) was melted and a high temperature superconductor crystal was obtained was examined. As a result, it was confirmed that the maximum temperature was in the range of 864 to 870 ° C., the holding time was within 2 hours, and the cooling rate was 850 ° C. or higher and 5 ° C./hour or lower.

Next, the superconducting composite obtained in Example 1 was abutted in the same manner as in Example 2, and the tips of both abutted silver plates were caulked and fixed, and then the thickness different from the above was applied. Green sheet (D) obtained above on a 0.1 mm silver plate,
That is, the high temperature superconductor precursor (D) was thermocompression bonded at 60 ° C. under the condition of 10 MPa to obtain a composite material. Then, the part of the high temperature superconductor composite (D) of the composite material was placed on the upper side between the high temperature superconductors of the superconducting composite, with the part of the high temperature superconductor composite (D) facing downward, and the following heat treatment was performed at 867 ° C. A high temperature superconducting junction was obtained through the same steps as described above.

The joint and the periphery thereof of the high temperature superconducting joint obtained above were observed by a microscope and an X-ray diffraction method, and Jc was measured by a four-terminal method. As a result, the Jc of the high temperature superconductor at a liquid nitrogen temperature of 77.3K was 8600 A / mm ² before joining.
And 8800 A / mm ² after joining, and J
c is a value calculated from the thickness of the superconductor film at the joint portion, which is 630.
It was 0 A / mm ² . In addition, the joined state of the joined portion was free of abnormal irregularities, foaming, different phases, etc. due to the flow of the high-temperature superconductor, and good joining was obtained.

[0036]

EFFECTS OF THE INVENTION The high-temperature superconducting joint obtained by the manufacturing method of the present invention does not deteriorate the superconducting properties of the high-temperature superconductor to be joined, and the superconducting crystal at the joint can be highly oriented. A good superconducting junction can be obtained. Further, according to the present invention, it is possible to apply even when a defect occurs in a part of the high temperature superconductor and it is necessary to repair the high temperature superconductor.

[Brief description of drawings]

FIG. 1A is a plan view showing a manufacturing operation state of a high temperature superconducting assembly according to an embodiment of the present invention, and FIG. 1B is a sectional view thereof.

FIG. 2A is a plan view showing a manufacturing operation state of a high temperature superconducting assembly according to another embodiment of the present invention, and FIG. 2B is a sectional view thereof.

[Explanation of symbols]

 1, 1'Silver plate 2, 2'High temperature superconductor 3 High temperature superconductor precursor (B) 4 Crimped part 5 Composite material 6 Silver plate 7 High temperature superconductor precursor (C)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichiro Shimoda 4-13-1, Higashimachi, Hitachi, Ibaraki Prefecture Ibaraki Research Laboratory, Hitachi Chemical Co., Ltd. (72) Inventor Toranosuke Ashizawa 4-13, Higashimachi, Ibaraki No. 1 Hitachi Chemical Co., Ltd. Ibaraki Research Center

Claims (8)

[Claims] 1. A method for joining high-temperature superconductors formed on a base material, wherein a high-temperature superconductor precursor is interposed between the high-temperature superconductors to be joined to form a high-temperature superconductor crystal formed on the base material. A high temperature characterized in that it does not decompose and / or melt, and that a part of the high-temperature superconductor precursor is melted, and then the whole high-temperature superconductor precursor is heated to a temperature at which the high-temperature superconductors are joined together. Superconducting junction manufacturing method. 2. The high-temperature superconductor precursor applied between the high-temperature superconductors to be joined is a liquid high-temperature superconductor precursor applied or a sheet-shaped high-temperature superconductor precursor joined. Method for manufacturing high temperature superconducting joints. 3. A method for joining high-temperature superconductors formed on a base material to each other, wherein a film of a high-temperature superconductor precursor is formed on a noble metal plate to obtain a composite material, and then the high-temperature superconductor of the composite material. The high temperature superconductor crystal formed on the base material is not decomposed and / or melted after being placed on the upper part between the high temperature superconductors to be joined with the film portion of the precursor facing downward A method for producing a high temperature superconducting joined body, characterized in that a part of the superconductor precursor is melted and then heated at a temperature at which the whole high temperature superconductor precursor is crystallized to join the high temperature superconductors to each other. 4. A high-temperature superconductor crystal powder having the same crystal structure as that of the high-temperature superconductor to which the high-temperature superconductor precursor is to be bonded.
The method for producing a high temperature superconducting joint according to claim 1, 2 or 3, wherein the content is less than or equal to wt%. 5. The high-temperature superconductor and the high-temperature superconductor precursor are a Bi-based high-temperature superconductor 2212 phase.
Alternatively, the method for producing the high temperature superconducting assembly according to item 4. 6. The high temperature superconductor according to claim 1, 2, 3, 4 or 5, wherein the composition of the high temperature superconductor precursor is a Bi-based high temperature superconductor 2212 phase composition obtained by mixing and calcining raw materials. Superconducting junction manufacturing method. 7. The composition of the high-temperature superconductor precursor is a Bi-based high-temperature superconductor 2212 phase composition in which two or more kinds of powders obtained by mixing raw materials, calcining and / or melting and then pulverizing are further mixed. Item 6. A method for producing a high temperature superconducting joint according to item 1, 2, 3, 4 or 5. 8. The method for producing a high temperature superconducting assembly according to claim 3, 4, 5, 6 or 7, wherein the noble metal plate is silver or an alloy plate containing silver as a main component.